Blast furnace hot-blast velocity control



April 20, 1954 F. LUCKEY BLAST FURNACE HOT-BLAST VELOCITY CONTROL Filed July 24, 1951 NGI I INVENTOR: FRANK L. LUCKEY 'ATT'YS Patented Apr. 20, 1954 UNITED STATES ATENT BLAST FURNACE HOT-BLAST VELOCITY CONTROL Frank L. Luckey, Gary, Ind.

Application July 24, 1951, Serial No. 238,333

Claims. 1

This invention relates to tuyere devices for blast furnaces and is particularly directed to structural improvements which enable the operator to modify the inflow of heated air at different parts of the furnace to overcome local conditions that are detrimental to the efiicient operation of the furnace.

This invention, accompanied by proven practice procedures, can reduce the cost per ton of pig iron by maintaining better combustion and heat concentration within the hearth of the furnace. whereby the gases are caused to work up through the mass of material or burden in controlled distribution and so as to avoid irregularities such as slipping or rolling.

The main objects of this invention are to provide improved means for hot blast velocity control so as to increase blast furnace tonnage; to provide improved means for causing the blower to apply more heat to cold tuyeres and to keep the furnace running uniformly and closer to its production capacity; to provide improved means for controlling the amount of air flow at individual tuyeres without impairing the velocity of the air and Without interfering with the visibility of local conditions in the hearth adjacent the tuyeres, observation of which guides the operator in the manipulation of the control devices and to provide an improved form and arrangement of the tuyere and its blow pipe to assure better operating conditions, reducing the risk of burning bronzes and thus prevent the loss of time in changing the burned bronze, which results from improper maintenance of furnace conditions.

Existing methods of combating irregularities due to frozen ore, wet material, moisture in the air, or for any other conditions that causes the hearth to be chilled, have been to cut the wind, take off ore, increase the coke input, and raise the kindling temperature. The result of such practice is usually low tonnage for a long time accompanied by high coke consumption, delays, burned bronze and off-grade iron.

With my improved apparatus, the wind would be cut in volume but maintained at the same velocity with the same amount of penetration into the mass of the hearth contents. Reduction in the volume of air flow under these conditions allows the gases to work up through the stock more uniformly, avoiding slipping or rolling and producing better and more complete combustion. Proper control of velocity will increase the output in tonnage of iron; improve the coke practice; improve the quality of pig iron even on a lean furnace; apply more heat to cold tuyeres; and avoid much of the necessity of research incidental to existing methods of operation; will reduce the formation of flue-dust by smoother furnace operation; will save labor in banking a furnace; and result in substantial economy in blowing-in and starting-up after banks.

A specific embodiment of this invention is illustrated in the accompanying drawings in which:

Figure 1 is a. sectional elevation showing the improved tuyere and its blast control devices in their relation to a blast furnace wall.

Fig. 2 is a schematic diagram including a crosssection of the blow pipe on the line 22 of Fig. 1 and indicating in the background a valve gate of suitable form for controlling the flow of air through the internal passages of the blow pipe.

In the drawings, the structure of a single tuyere assemblage is shown but it will be understood that each furnace would have a large number of such tuyeres uniformly distributed around the walls of its hearth; for example, a cupola twentyeight feet in diameter would have about twenty tuyeres in its periphery.

In the form shown, the furnace wall Ill might consist of an outer shell of steel lined with firebrick and have formed therein inwardly tapered notches II for the receipt of tuyeres 12. The notches are Water-cooled, as is indicated by the jacket It in Fig. 1.

The tuyere I2 has accordingly a sonically tapered periphery that fits the inner wall of the notch ll near the inner surface of the furnace wall. The bore M of the tuyre is of uniform diameter throughout its length, except at the front end where it has a conical counterbore l5 that serves as a seat for the end W of the blow pipe I! which is beveled to fit the conical seat IS.

The interior of the blow pipe i5 is subdivided by planar longitudinal partitions l 8 and H! which extend through it from side-to-side and end-toend and are horizontally disposed and parallel to each other, as shown in Fig. 2. The outer end portion of the blow pipe I? has a cylindrical bore and the walls of the inner end portion of said blow pipe which is adjacent to the tuyere l2 are tapered convergently toward the tuyere with its conical elements converging so as to focus the air blast at a point approximately 40 inches inside the wall of the furnace.

The blow pipe has an external collar-like enlargement 29 that provides an annular shoulder 2! serving as an abutment for a separate collar 22 which fits the outer peripheral end portion of the blow pipe and bears against the shoulder 2! for connecting the blow pipe 51 to the housing of a gate valve 23. The valve 23 has a gate 24 with a threaded stem 25 that coacts with a hand wheel 26 whereby the gate is raised and lowered.

The surface of the gate M which is adjacent the blow pipe ii is planar and the adjacent end i the blow pipe is extended into the valve body so that the partitions l8 and l9 fit against the face of the gate 2d. The gate 2 5 is of such form, as is shown in Fig. ,2, that it will completely close the passage through the blow pipe I! and may be shifted so as to open the passages C, C plus B, or C plus B plus A to the air blast.

The valve 23 is connected to the bustle pipe or ring main 21 by goose-neck piping made up of elbow fittings 28 and 29. The fitting 28 has a window 39 through which the operator may observe the condition of the contents of the hearth in each of the open positions of the gate. The fitting 29 has an arm 3! that is connected by a bridle in the form of a tension rod 32 removably attached as by a hook-and-eye structure 33 to the wall 19 of the furnace and there is a compression spring 34 bearing against the arm 3| and a nut 35 on the rod 32 that yieldingly holds the end 16 of the blow pipe into snug engagement the seat lb of the tuyere.

There is usually some variation in the distance between the ring main 2? and the seats 15 of the individual tuyere nozzles l2, and inasmuch as the blowpipe l l is preferably made of cast iron, the portion thereof between the collar 29 and the face of the valve gate 24 is made of a standard length, somewhat greater than is needed, so that the shoulder 21, the adjacent end of the hub 31 of collar 22 and the end 36 of the blowpipe may be milled to exact dimensions for the individual tuyres. The bridle 32 assures that the blowpipe ll will be securely held against the seat of the tuyere nozzle 52. Sufficient movement for this last purpose can be provided by slotting the flange 38 at points where it is connected by bolts 39 to the part 29 of the gooseneck.

The partitions l8 and 19 are so located in the blowpipe H as to divide the effective passage in definite ratios. For example, the area of passage C might be equivalent to that of a 5 inch pipe, that of passages 0' plus B might be equivalent to a 6 inch pipe, and that of passages C plus 13 plus A might be equivalent to a '7 inch pipe. The blowpipe I! is internally tapered at 40 to converge toward the tuyere nozzle for a length of about 12 inches so that its conical surface elements would focus at a point about 40 inches beyond the inner end of the tuyere !2. The blowpipe i! is of uniform diameter for most of its length at its outer end and the partitions l8 and i9 are parallel to each other and to the axis of the blowpipe throughout the length of the latter. By this arrangement, the shifting of the gate 2 3 changes the volume of air delivered to the tuyere while the velocity remains substantially constant.

The operation of the device shown is as follows:

When it is desired to bank the furnace, the supply of air at all tuyeres can be cut off by closing the valve gates 24.

An operator familiar with blast furnace practice can determine by looking into the sight aperture 30 whether the furnace is functioning properly in the vicinity of the respective tuyre and whether or not the efficiency of the furnace can be improved by increasing or reducing the volume of air blast to combat an irregularity in the temperature of the hearth. By this control of air flow more economy will be experienced in blowing-in and starting-up after the furnace has been banked. Using less volume to combat irregularties allows the gases to work up through the stock without the furnace slipping or rolling, and results in better combustion. When using a tuyere combination of different sizes, the tuyeres that usually appear colder than the rest should be favored by the smaller orifice.

Although but one specific embodiment of this invention is herein shown and described, it will be understood that numerous details of the structure shown may be altered or omitted without departing from the spirit of the invention as defined by the following claims.

I claim:

1. A blast furnace tuyre blow pipe having a planar horizontal longitudinal partition subdividing its interior into vertically spaced parallel open-ended air passages, in combination with valve means located at the outer end of said duct and coacting with said partition to selectively control the effective transverse area of the blast delivered by said blow pipe.

2. A blast furnace tuyere blow pipe having a plurality of planar horizontal longitudinal partitions subdividing its interior into vertically spaced parallel open-ended air passages, in combination with valve means located at the outer end of said duct and coacting with said partitions to selectively control the effective transverse area of the blast delivered by said blow pipe.

3. A blast furnace tuyere blow pipe having a planar horizontal longitudinal partition subdividing its interior from side-to-side into sepa rate vertically spaced channels, and a gate valve movable vertically across said channel and coacting with said partition to open and close said channels to selectively vary the effective transverse area of the air blast delivered by said blow pipe.

4. A blast furnace tuyre duct comprising a nozzle and a blow pipe leading thereto, said blow pipe having a planar horizontal longitudinal partition extending across its interior from side-toside and throughout substantially its entire length, and a valve gate movable vertically across said walls and partition and having one edge shaped to register with said partition for complete closure of one or both of the passages at opposite sides of said partition for selectively changing the transverse area of the blast delivered by said blow pipe.

5. A blast furnace tuyere duct comprising a nozzle and a blow pipe leading thereto, said blow pipe having a plurality of relatively thin vertically spaced horizontal planar longitudinal partitions extending across its interior from side-toside and throughout substantially its entire length to form a plurality of vertically spaced longitudinal passages, a valve gate movable vertically across said walls and partitions and having one edge shaped to register with said partitions for complete closure of the passages through said blow pipe and for complete opening one or more adjacent passages for selectively changing the area of the blast delivered by said blow pipe.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 58,145 Sinnott et a1. Sept. 18, 1866 872,904 Connolly Dec. 3, 1907 1,005,359 Symons Oct. 10, 1911 2,087,842 Gerwig July 20, 1937 2,334,314 Campbell Nov. 16, 1943 FOREIGN PATENTS Number Country Date 103,059 Germany May 20, 1899 103,924 Germany June 19, 1899 459,339 Germany May 2, 1928 337,843 Italy Mar. 13, 1936 

